1. Field of the Invention
This invention relates to polymeric dispersant additives for lubricating oils and hydrocarbon fuels. More particularly, this invention relates to substantially saturated copolymers comprising ethylene and one or more C.sub.3 to C.sub.28 alpha-olefin, preferably propylene, which has been grafted with an ethylenically unsaturated carboxylic acid material, and thereafter reacted with an adduct of a C.sub.5 -C.sub.9 lactone and a polyfunctional amine which is terminated on one end by a primary or secondary amino group, and on the other end by a tertiary amine-containing heterocyclic ring group to produce a polymeric product having both ester and amide linkages and characterized by improved dispersant performance.
2. Prior Art
Polymeric dispersant additives based on olefin copolymer-unsaturated acid material adducts are well known in the art. These additives act to keep sludge and varnish dispersed in engine oils and have been used with commercial success.
It is also known to react such olefin copolymer-unsaturated acid material adducts with polyfunctional compounds such as polyamines, polyols, amino alcohols, and mixtures thereof to form multifunctional polymeric reaction products. These multifunctional products have been used as dispersant additives for lubricating oils and hydrocarbon fuels and as viscosity index improvers for lubricants.
It is also known that polymers of 6 to 10 membered lactones such as valerolactone or E-caprolactone can be prepared by reacting the lactone monomer with a hydroxyl or amine initiator. When reacting E-caprolactone, for example, the polymerization reaction may be illustrated by the following equations: ##STR1##
The reactions are known to be catalyzed by various esterification catalysts such as stannous octanoate, and a variety of different molecular weight products are feasible depending upon the ratio of lactone to initiator. Molecular weights on the order of from a few hundred up to about 5000 are reproducably achievable.
Caprolactone can also be polymerized to a very high molecular weight, e.g., on the order of 100,000 or more. Typically such high molecular weight polymers do not employ initiators and preservation of functionality is not a requirement.
It is also known to react a lactone such as E-caprolactone with a polyamine to form a polyactone polymers which are terminated on one end by a tertiary amine group, and on the other end by a hydroxy group. Polyactone polymers of the type are useful for neutralizing certain sulfonic acid-containing polymers, such as lightly sulfonated polystyrene or sulfonated EPDM. The neutralized sulfonated polymers have a variety of applications such as viscosity modifiers for oils and surfactants. It has now been found that improved oil soluble dispersant additives, useful in fuel and lubricating oil compositions, including concentrates containing the additives, can be prepared by reacting an ethylene-alpha-olefin copolymer, which has been grafted by an ethylenically unsaturated carboxylic acid material, with an adduct of a C.sub.5 -C.sub.9 lactone and a polyfunctional amine which is terminated on one end with a primary or secondary amino group, and on the other end with a tertiary amino group and/or a heterocyclic ring which upon reaction with the grafted ethylene copolymer produces an ester amide with improved varnish performance.
While there are a number of prior art disclosures relating to lactone polymerization and ring opening reactions, and to polymeric materials which incorporate nitrogen and/or oxygen and which exhibit dispersant and/or viscosity index improving characteristics, in general, little or no prior art of direct pertinance appears to have surfaced in regard to the present polymeric dispersant additives. Exemplary of the patent literature which relates to lactone ring opening and polymerization processes and/or to oil soluble acid grafted ethylene copolymer dispersant additives are the following U.S. Patents: U.S. Pat. No. 4,362,636 discloses synthetic ester oils which are esterification products of monoalcohols and dicarboxylic acids or of polyhydric alcohols and monocarboxylic acids respectively, containing 5 to 45% by weight of units of hydrocarboxylic acids obtained from aliphatic alcohols, aliphatic, cycloaliphatic or aromatic carboxylic acids, and lactones of aliphatic C.sub.5 -C.sub.12 hydrocarboxylic acids. The synthetic ester oils are suitable for the preparation of lubricants and lubricant compositions.
U.S. Pat. No. 2,890,208 discloses a process for polymerizing lactones to form polyesters that are useful as plasticizers.
U.S. Pat. No. 4,062,786 and its continuation-in-part, U.S. Pat. No. 4,292,184, disclose lactone oxazoline reaction products of hydrocarbon substituted lactone carboxylic acids such as polybutyl lactone carboxylic acid, with a 2,2-disubstituted-2-amino-1-alkanol such as tris-(hydroxy-methyl) aminomethane (THAM). The reaction products and their derivatives are disclosed as being useful additives in oleaginous compositions such as sludge dispersants for lubricating oil.
U.S. Pat. No. 3,219,666 discloses as dispersing agents in lubricants, derivatives of polyalkenyl succinic acids and nitrogen compounds, including polyamines. The preferred molecular weight of the polyalkenyl moieties is 750-5000.
U.S. Pat. No. 4,379,914 and its continuation-in-part, U.S. Pat. No. 4,463,168, disclose the preparation of polycaprolactone polymers by reacting E-caprolactone with a diamine wherein one of the amine groups of the diamine is a tertiary amine and the other is a primary or secondary amine. The polycaprolactone polymers are disclosed as being useful for neutralizing certain sulfonic acid-containing polymers to form amine-neutralized, sulfonated derivatives which can be combined with an alkyl benzene sulfonic acid to give a surfactant which contains ester groups, hydroxyl groups and amine-neutralized sulfonate groups.
U.S. Pat. No. 3,316,177 teaches ethylene copolymers such as ethylene-propylene, or ethylene-propylene-diene, which are heated to elevated temperatures in the presence of oxygen so as to oxidize the polymer and cause its reaction with maleic anhydride which is present during the oxidation. The resulting polymer can then be reacted with alkylene polyamines.
U.S. Pat. No. 4,169,063 discloses the reaction of an ethylene copolymer in the absence of oxygen and chlorine at temperatures of 150.degree. to 250.degree. C. with maleic anhydride followed by reaction with polyamine.
U.S. Pat. No. 4,132,661 teaches to graft an ethylene copolymer, using peroxide and/or air blowing, with maleic anhydride and then to react the grafted copolymer with a primary-tertiary diamine.
U.S. Pat. No. 4,160,739 teaches an ethylene copolymer which is grafted, using a free radical technique, with alternating maleic anhydride and a second polymerizable monomer such as methacrylic acid, which materials are reacted with an amine having a single primary, or a single secondary amine group.
U.S. Pat. No. 4,171,273 discloses the reaction of an ethylene copolymer with maleic anhydride in the presence of a free radical initiator and then the reaction with mixtures of C.sub.4 to C.sub.12 n-alcohol and amine such as N-aminopropyl morpholine or dimethylamino propyl amine to form a V. I.-dispersant-pour depressant additive.
U.S. Pat. No. 4,219,432 teaches the reaction of maleic anhydride grafted ethylene copolymers with a mixture of an amine having only one primary group together with a second amine having two or more primary groups.
U.S. Pat. No. 3,169,945 discloses the preparation of lactone polyesters which are useful as plasticizers and as intermediates for preparing elastomers and forms. The polyesters can be prepared by reacting a lactone such as E-caprolactone with an initiator such as an alcohol, an amino alcohol, or an amine, including polyamines containing a heterocyclic ring group.
U.S. Pat. No. 3,436,463 relates to nematocidal and insecticidal compounds of N-substituted gamma hydroxycarboxylic acid amides. Among the disclosed compounds are the adduct of amines such as N-amino-propylmorpholine and gamma-butyrolactone or gamma-valerolactone.
U.S. Pat. No. 4,089,794 relates to polymeric dispersant additives comprising ethylene-alpha-olefin copolymers which have been solution grafted with an ethylenically unsaturated carboxylic acid material, and thereafter reacted with a polyfunctional material such as a polyamine, polyol or an amino alcohol.
U.S. Pat. No. 3,326,804 discloses improving the sludge dispersant properties of oleaginous compositions by adding thereto the reaction product of a polyalkylene polyamine with the product obtained by grafting maleic anhydride onto hydroperoxidized ethylene copolymer.
U.S. Pat. No. 3,404,091 discloses grafted polar monomers, such as acrylonitrole or methylacrylamide, onto hydroperoxidized copolymers of ethylene and propylene to produce multifunctional additives.
U.S. Pat. No. 3,687,849 relates to grafts of various unsaturated monomers including unsaturated polybasic acids, including maleic anhydride, onto a degraded, hydroperoxidized, interpolymers of ethylene and propylene (see also U.S. Pat. Nos. 3,388,067, 3,687,905 and 3,785,980).
U.S. Pat. No. 4,234,435 discloses as oil additives, polyalkylene substituted dicarboxylic acids derived from polyalkylenes having a M.sub.n of 1300 to 5000 and containing at least 1.3 dicarboxylic acid groups per polyalkylene. In Example 34 of this patent, a polyisobutene-substituted succinic acylating agent is reacted with caprolactam in the presence of mineral oil and sodium hydroxide.
U.S. Pat. No. 3,381,022 relates to ester derivatives of substantially saturated polymerized olefin-substituted succinic acid wherein the polymerized olefin substitutuent contains at least about 50 aliphatic carbon atoms and host a molecular weight of about 700 to 5000. The esters include the acidic esters, diesters, and metal salt esters wherein the ester moiety is derived from monohydric and polyhydric alcohols, phenols and naphthols. The ester derivatives are disclosed to be useful as additives in lubricating compositions, fuels, hydrocarbon oils and power transmission fluids. A related application, i.e., U.S. Pat. No. 3,522,179, relates to lubricating compositions comprising a major amount of lubricating oil and a minor proportion of an ester derivative of a hydrocarbon-substituted succinic acid sufficient to improve the detergency of the lubricating composition. The ester derivatives are similar to those described in U.S. Pat. No. 3,381,022 and contain at least about 50 aliphatic carbon atoms. The hydrogen substituent may be derived from a polymerized lower monoolefin having a molecular weight of from about 700 to about 5000.
U.S. Pat. No. 3,769,216 shows an atactic (i.e., noncrystalline) copolymer of ethylene and propylene containing from 45 to 65 mole percent of ethylene, mechanically degraded in the presence of oxygen followed by reaction with a polyamine.
U.S. Reissue Pat. No. 27,582 relates to oil additives derived from hydrocarbyl substituted succinic anhydride esters of N-hydroxyalkyl morpholines. A similar disclosure is contained in U.S. Pat. No. 4,435,297.
U.S. Pat. No. 3,651,028 is directed to copolymers of ethylene and maleic acid ester compounds which are modified by reaction with an amino alcohol such as a morpholine alcohol. The modified copolymers disclosed in this patent exhibit improved dye receptivity.
All of the above discussed patents are expressly incorporated herein by reference in their entirety.
Additional exemplary prior art disclosures, which are expressly incorporated herein by reference in their entirety are U.S. Pat. Nos. 4,402,844; 3,451,931; 3,248,187; 3,236,917; 3,202,678; 3,284,417; 3,455,827; 3,493,568; 4,086,294; 4,132,531; 4,261,871; 4,415,728; and 4,517,104.